Polybutene is a highly viscous polymer that originates from petroleum. This ingredient is similar in function and feel to polyisobutene, and it is commonly used as a base for viscous products, like gels or lip glosses.
Polybutene can control viscosity of skincare products through thickening the base formula. It can also serve as a binding agent, in which it prevents the other ingredients in the product from separating from one another. Additionally, this clear, colorless liquid is only compatible with oils, meaning it is insoluble in water, and often functions as a dimethicone alternative.